A. Field of the Invention
The present invention provides a method to identify and remove pathogen infected animals from a group/herd to prevent the spread of infection and preserve the health of the animals. In particular, PCR screening, utilizing primers appropriate to the pathogen, of both the animals and their environs unambiguously identifies active infections.
B. Description of Problem and Prior Art
Pathogens that infect farmed animals affect both the health and survival of the animals as well as the income of the farmers who raise the animals. For many pathogens, antibiotics are administered to the animals on an intermittent or continuing basis. However, the presence of the antibiotics or their by-products in consumable food products has raised concern about their long-term effect on human and animal health. Immunization against some pathogens is another possible approach, but vaccines for many animal diseases are either not available or are not cost effective. Yet, for other pathogenic organisms no antibiotic or vaccine treatment is available. Early detection of the infection and elimination/removal of the infected animals is the only method that can be used. However, serologic detection methods vary in their sensitivity especially during the early days of infection and may only detect an infection after the animal has started to make antibodies to the pathogen and may, itself, already be infectious.
One pathogen for which there is no effective treatment and no available vaccine is the pathogenic mink Aleutian Disease Virus (mADV). This virus was first described in 1956. All mink Aleutian Disease Viruses are single stranded DNA viruses of the parvovirus family. There are many strains of the virus, but only one known non-pathogenic strain (strain G) while the others are typically fatal. The pathogenic viral strains are absolutely devastating to mink farmers spreading quickly through mink colonies and contaminating the farm site through contact with the mink and their urine and feces. These viruses typically elicit a hyperimmune response in the mink with lethality arising from macro immuno-antigen complexes. The hypergammaglobulinemia condition inflames circulatory filtering organs such as the kidneys (glomerulonephropathy), spleen, and liver causing failure of these organs and death from the complications.
Attempts to find treatments for parvovirus infections have been reported. Alvarez et al. in U.S. Pat. No. 5,785,974 suggests that an immunogenic peptide in conjunction with other immunogenic complexes can be used to make a vaccine that can protect dogs, cats, pigs, and minks. However, the vaccines are proposed to be useful only against another parvovirus infection in mink, Mink Virus Enteritis (MVE) not the Mink Aleutian Disease Virus (mADV). Barney et al. In U.S. Pat. No. 6,054,265 describe peptides that can be used both for screening for certain viruses and for possible treatment. Among other viruses are listed the Mink Virus Enteritis (MVE) and the Aleutian Mink Virus (strain G). The patent basically deals with HIV identification and possible treatment methods are suggested for clinical treatment of infected patients. No direct application to infection with the deadly form of the Aleutian mink virus is discussed. Elford et al. In U.S. Pat. No. 6,248,782 teach that polyhydroxy benzoic acid derivatives are useful in the treatment of diseases caused by retroviruses as well as in the treatment of diseases caused by DNA parvoviruses. No specific example of treatment for mink Aleutian disease is given. As far as is known, none of the above suggested approaches to containing a fatal mink Aleutian disease outbreak has been successfully employed.
The inventive methods disclosed in this patent document are exemplified by the detection and eradication of pathogenic mink Aleutian disease virus from a farmed mammalian herd. However, the methodological approach taught here is applicable to detecting and eradicating pathogens from any farmed mammalian herd.